Your code shows that you have the same id used in two input fields. When you look at your code, you have two entries with this:
<input class=" w-100" type="text" id="email" name="email" value> <input class=" w-100" type="text" id="email" name="email" value="demo@gmail.com">
Either remove one of these input fields, or change the id to a different one. We can't tell you which one to choose because we don't know what you are trying to put the email into in the form.